the sg mrt system, like the bart system in the bay area, has a limited number of tracks per line, thus making it a non-24-hr system with a limited maintenance window of about 4 hours (after midnight to 4-5 am). most likely due to lack of regular track maintenance on the part of the previous management team, the mrt has reached a stage of wear and tear where it may be better to overhaul the track system instead of incremental and piecemeal improvements or repairs. in the bart system here, maintenance crews work on the tracks all morning during the maintenance windows everyday 7 days a week to check for misalignment, wear and tear of tracks, loose parts and joints and repair or replace them immediately. miles of tracks are realigned, repaired, and replaced daily. it's a continual process. vibrations, frequencies of trains, loads and speeds are factors contributing to misalignment, parts getting loose, wear and tear of the track system. the electrical system requires much maintenance too, but the mechanicals are most affected. if the former mrt management team did not pay much attention to these details and ensure constant maintenance of all tracks on a daily basis, eventual serious breakdowns would be inevitable. the lta and the transport ministry is correct in making sure best practice is observed and performed (which is not previously), and that a massive overhaul in oa&m is warranted in view of the sorry state and lack of maintenance of a truly well designed and planned system.